sounds like a classic case of atmospheric dust, swamp gas and lens flare which can be perfectly explained and debunked using an imaginary refractive index

A unique and promising method is outlined for determining the complex part of the index of refraction of atmospheric dust by utilizing measurements of diffuse and direct solar radiation. The solution requires comparison of measurements of the ratio of diffuse to direct solar radiation with theoretical calculations of the same values.

A knowledge of the ground albedo is necessary for the solution. The ground albedo may, in fact, also be determined from the measured ratios, but the solution in this case tends to he more sensitive to measurement than when the ground albedo is known.